platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/http_helpers.go

@@ -1,59 +1,18 @@
 package app
 
 import (
-	"encoding/json"
-	"log"
 	"net/http"
-	"time"
+	httpxpkg "selective-vpn-api/app/httpx"
 )
 
-// ---------------------------------------------------------------------
-// HTTP helpers
-// ---------------------------------------------------------------------
-
-// EN: Common HTTP helpers used by all endpoint groups for consistent JSON output,
-// EN: lightweight request timing logs, and health probing.
-// RU: Общие HTTP-хелперы для всех групп эндпоинтов: единый JSON-ответ,
-// RU: лёгкое логирование длительности запросов и health-check.
-
-// ---------------------------------------------------------------------
-// request logging
-// ---------------------------------------------------------------------
-
 func logRequests(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		start := time.Now()
-		next.ServeHTTP(w, r)
-		log.Printf("%s %s %s", r.Method, r.URL.Path, time.Since(start))
-	})
+	return httpxpkg.LogRequests(next)
 }
 
-// ---------------------------------------------------------------------
-// JSON response helper
-// ---------------------------------------------------------------------
-
 func writeJSON(w http.ResponseWriter, status int, v any) {
-	w.Header().Set("Content-Type", "application/json; charset=utf-8")
-	w.WriteHeader(status)
-	if v == nil {
-		return
-	}
-	if err := json.NewEncoder(w).Encode(v); err != nil {
-		log.Printf("writeJSON error: %v", err)
-	}
+	httpxpkg.WriteJSON(w, status, v)
 }
 
-// ---------------------------------------------------------------------
-// health endpoint
-// ---------------------------------------------------------------------
-
 func handleHealthz(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodGet {
-		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
-		return
-	}
-	writeJSON(w, http.StatusOK, map[string]string{
-		"status": "ok",
-		"time":   time.Now().Format(time.RFC3339),
-	})
+	httpxpkg.HandleHealthz(w, r)
 }